Year	1=extremely inefficient to 7=extremely efficient
2007	3.79661016949153
2008	3.37770473176599
2009	3.6701862439
2010	4.0657960196
2011	4.1
2012	4.1
2013	3.8
2014	3.2
2015	3.17985968423444
2016	3.2
2017	3.4